Device for Controlled Delivery of an Injectable Liquid

ABSTRACT

A device for the controlled delivery of an injectable liquid from a liquid container, wherein a flexible force transferor transfers the drive force of a drive wheel onto a piston which can be slid axially in the device, a permanently acting restoring force of a spiral spring is applied to the drive wheel to advance the piston and expel the liquid, and a lock locks the drive wheel against rotation and releases the drive wheel to expel the liquid. In one embodiment, the amount of liquid expelled can be indicated by audible clicks and, in one embodiment, the drive wheel moves only incrementally when the lock releases the drive wheel.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.10/650,521, filed on Aug. 28, 2003, which claims priority to GermanApplication No. 102 40 166.7, filed on Aug. 30, 2002, the contents ofwhich are incorporated in their entirety by reference herein.

BACKGROUND

The present invention relates to devices for delivering, dispensing,injecting, administering or infusion substances, and to methods ofmaking and using such devices. More particularly, it relates to a devicefor the controlled delivery of an injectable liquid, in one embodiment,from a preferably substantially cylindrical liquid container. Moreparticularly, the present invention relates to an injection device foradministering a liquid containing a therapeutic or medical active agent,for example insulin for the treatment of diabetes, from a syringe body.

Injection devices of the aforementioned type are known for example fromWO 95/09021. A syringe body for storing the liquid to be administered issealed off at a rear end by a piston which can be slid axially in thesyringe body, the liquid being delivered from an outlet at the front endof the syringe body when the piston is advanced towards the outlet.While in conventional injection devices comprising syringe bodies, theoverall length must correspond to at least twice the maximum stroke ofthe piston which can be slid in the syringe body, the overall length canbe reduced in injection devices of the aforementioned type by axiallydeviating a piston rod behind the syringe body, which drives the piston,away from its longitudinal axis. This is in particular advantageous inportable injection devices for autotherapy.

WO 95/09021 discloses a substantially incompressible, flexible pistonrod which is tightly guided in a guide in order to prevent the pistonrod from bending laterally away from its longitudinal axis. The pistonis advanced by controlled rotation of a threaded rod, the rotationalmovement being converted into an advancing movement by means of arotationally fixed but longitudinally slidable nut which engages withthe outer thread of the threaded rod and is connected to the rear end ofthe flexible piston rod. This mechanism is hardly suitable forhand-operated injection devices without an energy supply of their own.In addition, the drive mechanism is comparatively elaborate.

An injection device operating according to the aforementioned basicprinciple is disclosed in WO 98/57688. When an operating button isdepressed, a downward movement of a first gear rack is converted into anupward movement of a second gear rack which is coupled to a flexiblepiston rod. By rotating a dosage setting wheel, a stopper is adjustedwithin an adjustment range defined by maximum end positions, in order toset the dosage to be administered. The second gear rack can be maximallyslid only by the distance pre-set by the stopper. Furthermore, a firstspring is provided to reset the operating button, and a second springwhich is provided in a dosage setting mechanism. The two springs are notcoupled to the drive mechanism, in order to reset the latter and advancethe piston for delivering liquid from the syringe body. Although themechanism disclosed in WO 98/57688 can be operated by hand, it has acomparatively elaborate design.

SUMMARY

It is an object of the present invention to provide a generic devicecomprising a simpler mechanism which is hand-operable.

This object is addressed by a device for the controlled delivery of aninjectable liquid from a liquid container which is sealed off at a rearend by a piston which can be slid axially in said container in order todeliver the liquid from an outlet at a front end of the container, thedevice comprising, in one embodiment, a flexible force transferringmeans which is axially deviated, behind the container, away from thelongitudinal axis of the container; a drive mechanism which is coupledto said flexible force transferring means, in order to axially advancethe piston for delivering the liquid; and a restoring means, whereinsaid restoring means applies a restoring force to said drive mechanismand resets it for delivering liquid from the container, in order toadvance the piston via the flexible force transferring means.

In one embodiment, the present invention comprises a device for thecontrolled delivery of an injectable liquid from a liquid containerwherein: a flexible force transferring means transfers a drive force ofa rotatable drive wheel onto a piston which can be slid axially in thedevice, a restoring force of a spring is applied to the drive wheel tomove the piston, and a locking means locks the drive wheel againstrotation and releases the drive wheel for rotation. In one embodiment,the amount of liquid expelled may be indicated by audible clicks and, inone embodiment, the drive wheel moves incrementally when the lockingmeans releases the drive wheel.

In one embodiment, the present invention comprises a device for thecontrolled delivery of an injectable liquid from a liquid containerwherein: a flexible force transferring means transfers the drive forceof a drive wheel onto a piston which can be slid axially in the device,a preferably permanently acting restoring force of a spiral spring isapplied to the drive wheel in order to advance the piston and expel theliquid, and a locking means locks the drive wheel against rotation andreleases the drive wheel to expel the liquid. In one embodiment, theamount of liquid expelled can be indicated by audible clicks and, in oneembodiment, the drive wheel moves only incrementally when the lockingmechanism releases the drive wheel.

In accordance with the invention, the drive mechanism serving to advancethe piston is coupled to a restoring means which resets it fordelivering liquid from the container, in order to advance the piston viathe flexible force transferring means. The restoring means ischaracterized by a restoring force which applies a restoring force tothe drive mechanism. Thus, in accordance with the invention, a separatedrive motor for advancing the piston is not required, nor is acomplicated mechanism, for example a gear mechanism, to convert a driveforce of the drive motor into an advancement of the piston.

For delivering liquid, it is only necessary in accordance with theinvention to release the restoring force of the restoring means, whichcan be achieved by a simple release mechanism.

In one embodiment, the restoring force is preferably characterized by apreferential direction in which it resets the drive mechanism into anend position in which the restoring force is negligible and the drivemechanism no longer continues driving. The end position of the restoringmeans preferably corresponds to a front end position of the piston,where the piston is situated substantially at the front end of theliquid container.

In the direction opposite to the aforementioned preferential direction,by contrast, the drive mechanism is not driven by the restoring means.This ensures that, once the restoring force has been released, thepiston is driven towards the outlet of the liquid container.

Another advantage is that restoring means can be realized simply, forexample by means of pressure or tension springs or coil springs forgenerating a rotational restoring force. In principle, the restoringforce can also be generated in other ways, for example electrically,magnetically or pneumatically.

In some preferred embodiments, the restoring force is permanentlyapplied to the drive mechanism, in which case only a simple releasemechanism is provided to release the restoring force for advancing thepiston in the liquid container.

In some preferred embodiments, an adjustable, mechanical locking meansis provided, for a controlled release of the restoring force and to lockagainst angular adjustment of the drive wheel, except when the lockingmeans releases the rotational movement of the drive wheel. Mechanicallocking means can advantageously be realized in a simple way by means ofblocking pins, teeth or comparable latching protrusion and latchingrecesses. The present invention is not, however, in principle restrictedto mechanical locking means. Rather, the restoring force can also bereleased and/or blocked by electrical, magnetic or pneumatic means.

One simple embodiment results if the locking means is configured as asimple rocking lever which is moved to a releasing position, in whichthe drive mechanism is released, by advancing an operating button, andcan be reset into a locking position, in which the drive mechanism islocked, by a second restoring means. The rocking lever, or elementscooperating with it, comprises a mechanical blocking means, for examplea blocking projection, which cooperates with a corresponding mechanicalblocking means, for example a teeth on a lateral facing area of thedrive wheel.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention, including preferred embodiments,will now be described by way of example and by referring to theaccompanying drawings.

FIG. 1 depicts an injection device in accordance with one embodiment ofthe present invention, with the upper half-casing removed, in aperspective top view;

FIG. 2 depicts the device in accordance with FIG. 1, with the upperhalf-casing removed, in a top view;

FIG. 3 depicts the device in accordance with FIG. 1, from the rear side,without the outer half-casings, in a perspective view;

FIG. 4 depicts the device in accordance with FIG. 1, from the rear side,without the outer half-casings, in a top view;

FIG. 5 depicts an injection device in accordance with another embodimentof the present invention, with the upper half-casing removed, in aperspective top view;

FIG. 6 depicts the device in accordance with FIG. 5, with the upperhalf-casing removed, in a schematic top view.

In the figures, identical reference numerals indicate substantiallyidentical or substantially functionally identical elements andsub-assemblies.

DETAILED DESCRIPTION

FIG. 1 shows a perspective top view of one embodiment of an injectiondevice in accordance with the invention, with the upper half-casingremoved. The injection device comprises a substantially cylindricalsyringe body 1 which serves to store the liquid to be administered,which preferably contains a therapeutic or medical active agent, forexample insulin for treating diabetes. The syringe body 1 is sealed offat its rear end 4 by a piston (not shown) and comprises an injectionneedle 3 including a needle support 2 at its front end, said needlesupport being connected to the syringe body 1. The piston can be slidaxially in the syringe body and delivers liquid from the injectionneedle 3 when it is advanced towards the front end 2.

In one embodiment, a flexible force transferring means 5 is provided foradvancing the piston, wherein the front end of said force transferringmeans 5 abuts the piston (not shown) or is connected to it, preferablydetachably. The force transferring means 5 is preferably incompressibleand consists of a plastic or metal or comparable materials. As shown inFIG. 1, the force transferring means 5 is axially deviated, behind thesyringe body 1, away from the longitudinal axis of the syringe body 1,such that the overall length of the injection device shown can bereduced as compared to conventional injection devices. In the region 7,the force transferring means 5 is coupled, preferably fastened, to thedrive wheel 8 which serves as the drive mechanism, and serves totransfer the drive force generated by the drive mechanism 8 onto thepiston (not shown), in order to advance the latter into the syringe body1.

The drive wheel 8 is substantially circular and comprises an outertoothed area 27 in a first half on a lateral facing side and thefastening region 7, for coupling the force transferring means 5 to thedrive wheel 8, in a second half opposite the outer area 27. The drivewheel 8 comprises a handle 19 on its upper side, wherein said handleprotrudes through the upper half-casing (not shown) of the injectiondevice and can be operated from the outer side of the casing. The grip19 serves to rotate the drive wheel 8, in particular to reset the drivewheel 8 against the restoring force of the spiral spring 10 shown inFIGS. 3 and 4, which serves as the restoring means.

Radially inwardly, the flexible force transferring means 5 eitherdirectly abuts the outer circumference of the drive wheel 8 or abuts astay corresponding to the outer contour of the drive wheel 8, said stayprotruding substantially perpendicularly from the lower half-casing 21.Radially outwardly, the flexible force transferring means 5 abuts thestay 20 projecting substantially perpendicularly from the lowerhalf-casing 21. Furthermore, a guiding area is provided in the lowerhalf-casing 21 in the region between the outer circumference of thedrive wheel 8 or the radially inner stay (not shown) and the radiallyouter stay 20, as well as correspondingly in the upper half-casing (notshown), the flexible force transferring means 5 substantially abuttingsaid guiding area. Together, the stays and the guiding areas form aguide which tightly abuts the force transferring means, said guidepreventing or at least as far as possible inhibiting the forcetransferring means from bending laterally, away from its longitudinalaxis.

FIGS. 3 and 4, which show the first embodiment from the rear side in aperspective top view (FIG. 3) and a schematic top view (FIG. 4) with thelower half-casing 21 removed, show how a spiral spring 10 serving as therestoring means is connected to the drive wheel 8. At the radially outerend of the spiral spring 10, one end of the spring, bent away at a rightangle, is hung in a first fastening point 11, while at the radiallyinner end of the spring 10, a section of the spring, bent awaysubstantially at a right angle, is hung in a radially inner fasteningpoint 12. One of the two fastening points 11, 12 is connected to thelower half-casing (not shown), while the other of the fastening points11, 12 is connected to the drive wheel 8. Thus, the spring 10 biases thedrive wheel 8 against the half-casings of the injection device. The biasforce can be achieved by reversing the handle 19 (FIG. 1) or usingmotors. In some embodiments, the bias force is preferably of such amagnitude that the piston can be advanced between its rear end position,i.e., substantially the rear end 4 of the syringe body 1, and its frontend position, i.e., substantially the front end 2 of the syringe body 1,due to the restoring force of the spring 10.

Another suitable restoring means can be used instead of the spiralspring shown in FIGS. 3 and 4. The restoring means does not necessarilyneed to be directly connected to the drive wheel 8, but can also, forexample, act on its rotational mount in order to reverse it in theadvancing direction of the piston.

The spiral spring 10 shown in FIGS. 3 and 4 permanently applies therestoring force to the drive wheel 8. The present invention is not,however, restricted to a permanently acting restoring force. For lockingagainst angular adjustment of the drive wheel 8, a locking means isprovided, in particular in embodiments with a permanently actingrestoring force. In accordance with FIGS. 1 to 4, the locking means isformed by a rocking lever 14 which supports a blocking projection 15 atits front end, wherein said blocking projection 15 is formed tocorrespond to the outer teeth or toothed area 27 and cooperates with thesame, such that the drive wheel 8 is prevented from being turned furtherdue to the permanently acting restoring force.

The rocking lever 14 pivots about the rotational point 16 (FIG. 2)between the locking position shown in FIGS. 1 to 4, in which theengagement between the blocking projection 15 and the outer toothed area27 locks against angular adjustment of the drive wheel 8, and areleasing position in which the blocking projection 15 releases theengagement with the outer area 27 such that the drive wheel 8 is rotatedin the advancing direction of the piston, i.e. in FIG. 1,anti-clockwise, due to the restoring force of the spring 10.

The rocking lever 14 is connected via the joint 17 to the operatingbutton 13 which is linearly guided in lateral stays 23 of the lowerhalf-casing 21 and can be pushed into the casing of the injectiondevice. At the other end of the rocking lever 14, on the side of therotational point 16 opposite the joint 17, a leaf spring 18 serving as asecond restoring means acts on the rocking lever 14 in order to reverseit into the locking position.

In the injection device shown, in one embodiment, the maximum pistonstroke of the piston between the rear end 4 and the front end 2 of thesyringe body 1 corresponds to an angular adjustment of the drive wheel8, defined substantially by the radius of the guide 20 for the flexibleforce transferring means 5. Stoppers (not shown) are preferably providedin the casing and/or on the drive wheel 8 and/or on the flexible forcetransferring means 5, and limit the angular adjustment of the drivewheel 8 in its two end positions. Preferably, the maximum piston strokeof the piston in the syringe body 1 corresponds to the bending radius ofthe flexible force transferring means 5 multiplied by the number pi. Thepiston is thus slid between its rear and front end position by half arevolution of the drive wheel 8. Thus, in the embodiment shown in FIGS.1 to 4, the outer toothed area 27 can be arranged in a first half of thedrive wheel 8, while the fastening region 7, in the rear end position ofthe piston in the syringe body 1, is substantially arrangeddiametrically opposite the rear end 4 of the syringe body 1. The presentinvention is not, however, restricted to the aforementioned dimensions.

In order to even more flexibly exchange the syringe body 1, the frontend 24 of the lower half-casing 21 and/or the corresponding front end ofthe upper half-casing (not shown) can be removable, in order to make thesyringe body 1 fully accessible for exchanging. In some preferredembodiments, the front end 24 comprises a bearing area 25 on its innerside, said bearing area 25 being formed to correspond exactly to theouter contour of the syringe body 1, in order to securely store it. Inorder to insert the syringe body 1 into the bearing area 25 of the frontend 24 of the injection device in an exact fit, the rear end 4 of thesyringe body 1 comprises the flattened portion 29 visible in FIGS. 2, 3and 5. The piston of the syringe body 1 can be retracted by reversingthe drive wheel 8 against the restoring force of the spring 10. Thesyringe body 1 can then be removed from the casing.

In one embodiment the injection device may be operated as follows: theflexible force transferring means 5 is retracted by reversing the drivewheel 8, clockwise in FIG. 1. At the same time, the piston (not shown)can also be moved to its rear end position near the rear end 4 of thesyringe body 1. Once the front half-casing 24 has been removed, thesyringe body 1 can be replaced with a new syringe body. The flexibleforce transferring means 5 is then moved back to abut the piston or isconnected to it. The piston is then sufficiently advanced, for exampleto prime the syringe body. In the rear end position which the pistonthen reaches, the blocking projection 15 engages with the outer toothedarea 27 of the drive wheel 8 and locks against its angular adjustment.In this position, the front end of the operating button 13 protrudes outof the lower half-casing 21.

Pushing the operating button 13 into the casing releases the blockingprojection 15 from the outer toothed area 27, such that there is acontrolled release of the restoring force by the locking means. Lastly,the engagement between the blocking projection 15 and the outer toothedarea 27 is completely or substantially completely released. Due to therestoring force of the spring 10, the drive wheel 8 then turns,anti-clockwise in FIG. 1, and thereby slaves the flexible forcetransferring means 5 connected to the drive wheel 8 in the region 7. Thefront end of the flexible and incompressible force transferring means 5,guided in the guide 20, is thus axially advanced in the syringe body 1and thereby slaves the piston stopper, such that liquid is deliveredfrom the injection needle 3.

As long as the operating button 13 is sufficiently pushed down, in orderto release the drive wheel 8, the piston is advanced into the syringebody 1 due to the restoring force, and liquid is expelled. While thedrive wheel 8 rotates, clearly audible clicks can be generated for theuser, for example because the teeth in the outer toothed area 27, ordosing protrusions attached at regular angular intervals to the facingsides or lateral areas of the drive wheel 8, abut an obstacle andthereby emit the click. In principle, the blocking projection 15 shownin the figures is also suitable as an obstacle, providing the distancebetween the blocking projection 15 and the teeth of the outer toothedarea 27 is sufficiently small in the releasing position of the rockinglever 14 that on the one hand the blocking projection 15 and the outertoothed area 27 abut, but on the other this does not prevent the drivewheel 8 from turning further.

The restoring force of the spring 10 serving as the restoring means canbe adjusted to the flow resistance of the liquid as it is delivered fromthe syringe body 1, such that there remains enough time for the user tocount out the clicks and so work out the dosage of liquid actuallydelivered.

The user then lets go of the operating button 13 again. Due to therestoring force of the leaf spring 18 serving as the second restoringmeans, and/or a spring (not shown) which pushes the operating button 13back out of the casing, the rocking lever 14 is reset into the lockingposition. Because the steep flanks of the serrated-toothed outer toothedarea 27 each lie on the side of the tooth flanks of the outer toothedarea 27 lying in the restoring direction, the correspondingly formedblocking projection 15 is automatically returned to the locking positionas soon as a front end of the blocking projection 15 comes to abut oneof the tooth flanks of the outer toothed area 27. The expulsion ofliquid is thus automatically terminated when the user lets go of theoperating button 13.

In principle, however, it can also be provided that the restoring forceof the leaf spring 18 and/or the spring (not shown) which pushes theoperating button 13 back out of the casing are too small to move theblocking projection 15 back into engagement with the toothed area 27,when the drive wheel 8 is turning. In such an embodiment, the entiredosage of liquid still available in the syringe body 1 would then becompletely administered.

To even more simply dose the amount of liquid actually delivered usingthe injection device in accordance with the invention, the locking meansis configured, in another embodiment shown in FIGS. 5 and 6, such thatthe piston can only be moved a fraction of the maximum piston strokepre-set by the front and rear end positions of the piston in the syringebody 1. In principle, identical reference numerals in FIGS. 5 and 6indicate identical components and functional groups, such that adescription of them is omitted below for reasons of clarity.

FIGS. 5 and 6 show a second embodiment of the injection device inaccordance with the invention from above, with the upper half-casingremoved, in a perspective top view and a schematic top view. Inaccordance with the second embodiment, the rocking lever 14 as a wholeis formed substantially L-shaped. The upper limb of the rocking lever 14is jointed via a joint 17 coupled to the operating button 13. The lowerlimb of the rocking lever 14 comprises two blocking projections 30, 31arranged on opposite sides of the rotational point 16 of the rockinglever 14, which are each formed to correspond to the teeth of the outertoothed area 27 of the drive wheel 8, but which, as can be seen in FIG.6, are offset with respect to each other by half a tooth of the outertoothed area 27. Thus, if one of the blocking projections 30, 31 engagescompletely with the outer toothed area 27, then the other of theblocking projections 30, 31 is arranged approximately in the middle of atooth flank of the outer toothed area 27.

In the resting position of the operating button 13, shown in FIGS. 5 and6, the first blocking projection 30 engages with the outer toothed area27 and locks against angular adjustment of the drive wheel 8. If theoperating button 13 is then pushed down into the casing, the rockinglever 14 is pivoted about the rotational point 16 such that the firstblocking projection 30 is released from its engagement with the outertoothed area 27 and the second blocking projection 31 is moved to themiddle of the opposite tooth flank of the outer toothed area 27. Lastly,the second blocking projection 31 comes to abut the opposite toothflank. If the operating button 13 is pushed further down, the secondblocking projection 31 slides off, ultimately completely, on theopposite tooth flank and engages, ultimately completely, with the outertoothed area 27. In this position, the first blocking projection 30 ispreferably completely out of engagement with the outer toothed area 27and the drive wheel 8 has turned further by half a tooth flank,anti-clockwise in FIG. 6. This rotational movement of the drive wheel 8is assisted by the restoring force, acting in the same direction, of thespiral spring 10 serving as the restoring means (see FIGS. 3, 4).

The user then lets go of the operating button 13 again. Due to therestoring force of the leaf spring 18, serving as the second restoringmeans and abutting the rocking lever 14 in the region of the firstblocking projection 30, and of a spring (not shown) which pushes theoperating button 13 back out of the casing of the injection device, thesecond blocking projection 31 is gradually released from its engagementwith the outer toothed area 27 and the first blocking projection 30 ismoved back into engagement with the outer toothed area 27. Here, too,the first blocking projection 30 slides off, ultimately completely, onthe tooth flank opposite it until the first blocking projection 30engages, ultimately completely, with the outer toothed area 27 and locksagainst further angular adjustment of the drive wheel 8.

In accordance with the second embodiment, when the operating button 13is operated once, the drive wheel 8 is turned further by exactly onetooth flank of the outer toothed area 27. This corresponds to a minimumamount of liquid which can be dosed by the injection device. Operatingthe operating button 13 is easily tangible. The user can thus easily setthe dosage of liquid actually delivered by simply counting the number oftimes, however often, the operating button 13 is operated. When rotatingthe drive wheel 8, clicks can again be generated, as described above,such that the user can also select or calculate the dosage of liquid bysound.

In the above embodiments, the flexible force transferring means 5 ispreferably a cylindrical coil spring made of round wires having aconstant diameter. The cylindrical cross-section of coil springs enablesthem to be guided easily, for example using the stays 20 shown in thefigures, which project substantially perpendicularly from the lower orupper half-casing, or using comparable guiding means. In addition,metallic coil springs slide on the guiding stays described above,preferably formed from plastic, with comparatively little resistance.

In principle, however, the flexible force transferring means can also bemade from plastic, for example in the form of an articulated plasticband such as is disclosed in WO 98/01173, the content of which isexpressly incorporated herein by way of reference.

In the above embodiments, the drive wheel 8 can also be latched in waysother than using the outer toothed area 27 and the blocking projection15 which cooperates with it. Suitable teeth, texture or latchingprotrusions can, for example, be provided on an upper side of the drivewheel 8 or on a disc or the like coupled to a drive axle of the drivewheel 8, in order to cooperate with latching protrusions or the like ofa locking means. Suitable measures will become clear to the personskilled in the art when studying this application.

While it has been described above that the operating button 13 isoperated by hand by the user, a release mechanism operated using motorsor electromagnetically can of course also be provided to triggerdelivery of the liquid.

A preferred application of the injection device in accordance with theinvention is the injection of insulin into subcutaneous fatty tissue,for treating diabetes. The invention is not, however, restricted to thisapplication.

In the foregoing description, embodiments of the present invention,including preferred embodiments, have been presented for the purpose ofillustration and description. They are not intended to be exhaustive orto limit the invention to the precise form or steps disclosed. Obviousmodifications or variations are possible in light of the aboveteachings. The embodiments were chosen and described to provide the bestillustration of the principles of the invention and its practicalapplication, and to enable one of ordinary skill in the art to utilizethe invention in various embodiments and with various modifications asare suited to the particular use contemplated. All such modificationsand variations are within the scope of the invention as determined bythe appended claims when interpreted in accordance with the breadth theyare fairly, legally, and equitably entitled.

1. A device for the controlled delivery of an injectable liquid from aliquid container sealed at a rear end by a piston which can be movedaxially in the container to deliver the liquid from the container, thedevice comprising: a flexible force transferor axially deviated behindthe container away from a generally central longitudinal axis of thecontainer; a drive mechanism coupled to said transferor to axially movethe piston for delivering the liquid; a restorer applying a restoringforce to said drive mechanism and resetting said drive mechanism fordelivering liquid from the container, wherein the restorer permanentlyapplies said restoring force to the drive mechanism to reset the drivemechanism from a starting position in which the piston is situatedsubstantially at one end of the liquid container to an end position inwhich the piston is situated substantially at the other end of theliquid container; and a lock enabling a controlled movement of thepiston by a fraction of a maximum piston stroke pre-set by the startingand end positions of the piston in the liquid container.
 2. The deviceas set forth in claim 1, wherein the lock comprises a lever whichcomprises blocking projections on mutually opposite sides of arotational point of said lever.
 3. The device as set forth in claim 1,wherein the lock comprises a lever which comprises blocking projectionson mutually opposite sides of a rotational point of said lever, andwherein the drive mechanism comprises a drive wheel, said blockingprojections cooperating with the drive wheel.
 4. The device as set forthin claim 3, wherein the drive wheel carries teeth, the blockingprojections offset with respect to each other by a half a tooth of saidteeth.
 5. The device of claim 3, wherein the drive wheel movesincrementally when the lock releases the drive wheel.
 6. The device asset forth in claim 1, wherein the flexible force transferor comprises acylindrical coil spring coupled to a lateral facing area associated withthe drive mechanism.
 7. A device for the controlled delivery of aninjectable liquid from a liquid container sealed at a rear end by apiston which can be moved axially in the container to deliver the liquidfrom the container, the device comprising: a coil spring axiallydeviated behind the container away from a generally central longitudinalaxis of the container; a drive mechanism coupled to said coil spring toaxially move the piston for delivering the liquid; a spiral springapplying a restoring force to said drive mechanism and resetting saiddrive mechanism for delivering liquid from the container, wherein thespiral spring permanently applies said restoring force to the drivemechanism to reset the drive mechanism from a starting position in whichthe piston is situated substantially at one end of the liquid containerto an end position in which the piston is situated substantially at theother end of the liquid container; and a lock enabling a controlledmovement of the piston by a fraction of a maximum piston stroke pre-setby the starting and end positions of the piston in the liquid container.